Lethal Legacy, Linda Fairstein’s 11th novel, arrives in stores today—but its author has already received the uber-review from her uberfan. “Dear Linda, I loved
Lethal Legacy,” wrote Bill Clinton, on his cream-colored stationery, complete with presidential seal. “Thanks to you, I know more about New York than I ever dreamed I could. Now I need time to see it all from the Cloisters to the sewers to the stacks of the library! Thanks, Bill.”

"It’s my life ambition to read every Trollope novel—and in several books, Alex has been doing that."

Fairstein, of course,
has seen it all, both as a former Manhattan sex-crimes assistant district attorney, and as an author of bestselling books about, well, about a Manhattan sex-crimes assistant district attorney named Alex Cooper. (
Law & Order fans take note: The blond ADA on
SVU—Alex Cabot, initials A.C., get it?—is based on her, Fairstein says.) Sitting in an Upper East Side restaurant that just happens to have covers of several Fairstein books framed on the wall—Fairstein and her husband Justin Feldman are regulars here—we talk about her new book, her career, and her many alter egos.

As in many of your books, there’s a very famous New York crime at the start of
Lethal Legacy. Here, a woman is held captive by a guy who forces his way into her apartment by pretending to be a fireman. That sounds a lot like the
Peter Braunstein case of a few years back.

There are some similarities, but the thing I loved about that setup was that in the 30 years I was in the district attorney’s office, 28 of them in sex crimes, I’d never heard of somebody doing that. What woman would not open the door to a fireman, when she had smelled smoke in her hallway? So that’s what I wanted to use. I wanted to take a motive, a device, that I had never thought of—and then I went off into an entirely different story.

Obviously, your books are informed by your time in the DA’s office. But they’re also influenced by your passion for the institutions of New York. One book was set in Edgar Allan Poe’s house; sometimes characters go to the Cloisters or the sewers; this one examines secrets held inside the New York Public Library. Why the library, and why now?

I’ve always loved the physical building and I knew there were many rare stories inside. Back in 1974, before I was assigned to sex crimes, I’d prosecuted a man who’d started in Seattle and came across the country stealing rare books and valuable plates out of books in libraries. Then, years later, I read about another guy—E. Forbes Smiley, who did the same thing, only much more elaborate. I really always wanted to know about the library, but I put it off for maybe four or five books. I’ve kept a file [of library-related clips] for years.

How did you go about doing your research?

At first I thought they wouldn’t let me in, that I’m too crassly commercial, and they wouldn’t even entertain the idea of my looking around. But then a very close friend of mine, Louise Grunwald, who’s on the board, introduced me to David Ferriero, who’s the No. 2 there. We just bonded with each other. He put me in the hands of curators in the different private collections, people allowed me to hold and examine manuscripts that are centuries old, manuscripts like the last letter Keats wrote Fanny Brawne.

Um, a lot of your readers barely know who Keats was, let alone
Fanny Brawne—you must have been a pretty bookish sex crimes DA. Is Alex that way?

This material really did appeal to the English lit major in me. And yes, Alex does read a lot. It’s my life ambition to read every Trollope novel—and in several books, Alex has been doing that. She always has a crime novel on her night table—can’t read them in the middle of a major case—but she reads [Harlan] Coben, and has a crush on him. She is very drawn to tragic women in fiction—maybe because she can help ‘repair’ lives in her real life. So she might read
Anna Karenina (one of my favorites) and be thinking she could intervene and bring Anna to her senses. Or stop the train.

Once, years ago, I asked you about the differences between you and Alex, and you said, “She’s younger and thinner. . .”

And blonder...

Right, and blonder. But now, you’re an accomplished author, you’re older, and your books have gotten much more complex and sophisticated. How has Alex changed ?

She has aged unrealistically. There are 11 books (over at least as many years) and she’s only aged, two, two and a half years. (Would that it were so in life!) Unlike some of the characters set in real time—Ian Rankin’s guy, Kay Scarpetta is over 50 now—the changes in Alex are a little more subtle. I think I’m describing Alex’s evolution in terms of the impact the work has on her, internally, emotionally, how she relates to other people, how it effects her personal relationships, how it gets in the way of some of the men she’s dated. She’s sort of in a good place that way, but that’s not going to last for long...

What’s going to happen?

There’s a French guy, and she’s going to be commuting back and forth to France—which is actually based on a romance I had before I got married. (It was just too good material not to use.) There was a sense at the time that I would go live with him in the south of France, in this tiny village, where people don’t lock their doors at night. The sex crimes ADA’s fairy tale! But then, when I was seriously thinking about it, I took my best friend and we went over together and in three days, she said “I’ll shoot you if you do this and leave behind the kind of career and life you’ve got.”

So, it’s possible that in a future book, you’re actually going to take Alex out of New York? Would you ever “loan her out,” to another city?

I’d love to. Absolutely. We’d probably go abroad. London. Paris. I’d also love to do Washington, D.C. I think in the tradition of the great crime novels she’d have to have an LA caper. Her most loyal fans are very entrenched, though: They would probably go ballistic.